Effect of submental electrical stimulation on pharyngeal pressure generation

Purpose The aim of this study was to investigate the effects ofswallowing-triggered neuromuscular electrical stimulation (NMES)of the submental musculature on pharyngeal pressure generation inhealthy research participants during stimulation and up to 60 minthereafter.Methods Twenty healthy research participants [mean age = 23.7years (SD = 3.8), 10 females] performed 60 noneffortful salivaswallows at a rate of approximately one every 30 s. Each swallowtriggered a 4-s block of submental NMES, which consisted of 200-ls2stimuli applied at a rate of 80 Hz and an intensity of 75% of theindividual’s pain threshold utilising a treatment protocol identified toincrease motor evoked potentials to the submental muscle group(Doeltgen et al., in review). Pharyngeal pressures during bothAbstracts 363123non-effortful and effortful saliva swallows were measured at baseline,during stimulation and at 5, 30, and 60 min post-stimulation in theoropharynx, hypopharynx and, upper esophageal sphincter (UES).Results Effortful swallows produced greater pharyngeal pressure(p = 0.001), and lower UES relaxation pressure (p = 0.021), thannoneffortful swallows. Pharyngeal and UES pressures during stimulated and nonstimulated noneffortful swallows did not differ(p[0.05). At 30 and 60 min post stimulation, noneffortful swallowswere completed with lower pressures at all sensors (p = 0.025),whereas effortful swallows were not affected by stimulation(p[0.05).Conclusion Swallowing-triggered submental NMES has no immediate effects on pharyngeal pressure generation, whereas at 30 and 60min post stimulation, decreased pressure in the oro- and hypopharynxposes a potential risk for compromising airway protection and bolusflow. Decreased UES relaxation pressure may facilitate bolus transitat this level of the pharynx.